Example of Wpf drag/drop sliding effect in asp.net

In fact, it is very easy to support drag and drop in wpf. You can use drag events or custom mouse events.

Today, we will share a drag-and-drop slide effect with mouse clicks and up events.

First, define a ScrollViewer in xaml.

The code is as follows:

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<Window x: Class = "Wpf drag/drop sliding effect. MainWindow" Xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation" Xmlns: x = "http://schemas.microsoft.com/winfx/2006/xaml" Title = "MainWindow" Height = "400" Width = "680"> <Grid> <ScrollViewer Name = "viewer" Grid. Column = "0" Grid. Row = "1" Padding = "0, 0, 0" VerticalScrollBarVisibility = "Auto"> <Canvas Name = "canvas" Margin = "0, 0, 0" PreviewMouseDown = "canvas_PreviewMouseDown" PreviewMouseMove = "canvas_PreviewMouseMove" PreviewMouseUp = "canvas_PreviewMouseUp"> <Grid Name = "NGEntry">   </Grid> </Canvas> </ScrollViewer> </Grid> </Window>

Simulate button data in the background:

The code is as follows:

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/// <Summary> /// Create a button set /// </Summary> /// <Param name = "grid"> </param> Public void CreateNgEtry (ref Grid grid)  { Grid. Children. Clear (); Grid. RowDefinitions. Clear (); Grid. ColumnDefinitions. Clear (); For (int I = 0; I <6; I ++)      {      } For (int I = 0; I <18 + 1; I ++)      { Grid. RowDefinitions. Add (new RowDefinition ());      } For (int I = 0; I <18; I ++)      { Grid. ColumnDefinitions. Add (new ColumnDefinition ()); For (int j = 0; j <6; j ++)   { Button but = new Button (); But. Height = 80; But. Width = 110; But. FontSize = 16; Grid. Children. Add (); System. Windows. Controls. Grid. SetColumn (but, j ); System. Windows. Controls. Grid. SetRow (but, I ); But. Content = "Test" + I. ToString ();   }      }  }

Handle the event when you press the mouse, and remember the current position:

The code is as follows:	Copy code
Private void canvas_PreviewMouseDown (object sender, MouseButtonEventArgs e)  { TargetElement = Mouse. DirectlyOver as UIElement; If (targetElement! = Null)      { TargetPoint = e. GetPosition (NGEntry );      }  }

When dragging the mouse:

The code is as follows:	Copy code
Private void canvas_PreviewMouseMove (object sender, MouseEventArgs e)  { If (e. LeftButton = MouseButtonState. Pressed & targetElement! = Null)      { Var pCanvas = e. GetPosition (canvas ); Double gridtop = Convert. ToDouble (NGEntry. GetValue (Canvas. TopProperty )); NGEntry. SetValue (Canvas. TopProperty, pCanvas. Y-targetPoint. Y );          }  }

When you move the mouse down the event:

The code is as follows:

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Private void canvas_PreviewMouseUp (object sender, MouseButtonEventArgs e)  { Double gridtop = Convert. ToDouble (NGEntry. GetValue (Canvas. TopProperty )); Double gridh = NGEntry. ActualHeight; Double viewh = canvas. ActualHeight; If (gridtop> 0)      { NGEntry. SetValue (Canvas. TopProperty, 0d );      } If (viewh + (Math. Abs (gridtop)> gridh)      { NGEntry. SetValue (Canvas. TopProperty, viewh-gridh );      }  }